This invention relates generally to sensor fault detection and more particularly to sensor fault detection in redundant sensor feedback control systems.
Many engineering systems use sensors to monitor and control the operation of the system. That is, the sensors are used to measure one or more system variables such as speed, temperature, pressure and the like. The sensor outputs are then used as feedback in a closed-loop operation to ensure that the system is being operated at the desired conditions, that safety bounds are being observed, and that performance is being optimized.
Although sensors are generally designed to be robust, sensor failure is still a possibility that is often addressed through use of redundant sensors. In such redundant sensor systems, control logic is used to determine which sensor output is used in the feedback loop. Current selection schemes do not fully consider the expected system response relative to command inputs. They also fail to adequately detect certain failure signatures of the sensors in some instances. These failure modes are characterized by either intermittent noise bursts, which occur at levels too small to detect currently, and/or slow gain changes (e.g., drift), which are not observable with current selection schemes. Furthermore, current selection schemes tend to use very complex algorithms comprising multiple layers of logic.
It would be desirable, therefore, to provide a redundant-sensor, feedback control system that considers expected system response and has a sensor selection scheme that can better detect noise burst and gain drift failures in the sensors. It would further be desirable to achieve sensor selection using relatively compact logic.
The above-mentioned need is met by the present invention, which provides a system and method for controlling operation of a component. The system includes at least two sensors that are arranged to sense an operating condition of the component and a controller that controls the component in response to feedback signals output by one or more of the sensors. The controller also determines how the sensor feedback signals are to be used in controlling the component. To this end, the controller includes a model-based statistical filter for each one of the second sensors.
The present invention and its advantages over the prior art will become apparent upon reading the following detailed description and the appended claims with reference to the accompanying drawings.